Flammable hydrocarbons are generally used as energy sources but some situations may require their destruction, for instance in the event of a production surplus or an unexpected shutdown of equipment. Some flammable hydrocarbons are byproducts of natural or industrial processes where the source cannot be stopped and/or be easily controlled, and cannot be stored for a later use.
One example of source of a flammable gas that cannot be stopped and/or be easily controlled is a landfill site. In a landfill site, organic matter contained in the waste slowly decays over time using a natural process, generating a gas stream containing methane (CH4). Methane is a flammable gas and is mixed with other flammable and non-flammable gases in varying proportions when coming out of the landfill site. Methane gas is a valuable source of energy but is also a greenhouse gas if released directly into the atmosphere. Thus, if the methane gas contained in a gas stream coming out of a landfill site cannot be readily used or stored, it should be destroyed by combustion in a gas flare. Gas streams containing methane gas can also be created by other processes, for instance in an anaerobic digester. Many other situations and contexts exist.
Systems such as flare apparatus for burning and disposing of combustible gases and fluids are well known. Flare apparatus are commonly mounted on flare stacks and are located at production, refining, processing plants and the like for disposing of flammable waste gases or other flammable gas streams which are diverted for any reason, including, but not limited to venting, shut-downs, upsets and/or emergencies.
It is generally desirable that the flammable gas/liquid be burned without producing smoke and typically such smokeless or substantially smokeless burning is mandatory. One method for accomplishing smokeless burning is by supplying combustion air with a steam jet pump, which is sometimes referred to as an eductor. Combustion air insures the flammable gas is fully oxidized to prevent the production of smoke. Thus, steam is commonly used as a motive force to move air in a flare apparatus. When a sufficient amount of combustion air is supplied, and the supplied air mixes well with combustible gas, the steam/air mixture and flammable gas can be burned with minimal or no smoke.
In a typical flare apparatus, the required combustion air is supplied using motive force such as blower, a jet pump using steam, compressed air or other gas, along with obtaining air from the ambient atmosphere along the length of the flame.
U.S. Pat. No. 8,967,995, discloses a dual-pressure flare system which includes a dual-pressure flare stack having a central axis that is aligned with the center of a high-pressure outlet; a high-pressure flue having a central axis that is co-linear with the central axis of the dual-pressure flare stack; and a low-pressure flue connected to a low-pressure tip, and further includes an air-assist assembly having an air-supply connection connected to an air blower and a mixing chamber, wherein the mixing chamber surrounds the low-pressure tip.
U.S. Pat. No. 9,464,804 discloses gas flare system includes a vertical flare stack having an opened top end and a bottom floor wall, a burner arrangement provided through the bottom floor wall. The burner arrangement receives a waste gas stream from a waste gas circuit and also primary air. Secondary air orifices around the burner supply secondary air coming from a plenum housing located directly underneath the bottom floor wall.
EP 2636951 describes a combustion system comprising a combustion device, a heat exchanger and a stack. The combustion device is comprising a waste gas feed pipe, a support gas feed pipe, an air feed system, a mixing chamber for mixing air with waste gas and/or with support gas, and a gas permeable combustion surface onto which the waste gas will be burnt after the premix has flown through it, thereby producing flue gas. The stack connects the combustion device to the heat exchanger, thereby creating flue gas flow from the combustion device into the heat exchanger. The heat exchanger comprises channels for the flue gas and for at least one fluid to be heated.
U.S. Pat. No. 6,146,131 discloses a multiple burner assemblies fitted to the burner chamber consisting of upwardly directed nozzles for distributing the waste gas in the combustion chamber, as well as atomization of the waste gases and direct and discharge combustible waste gases upwardly into the burn chamber. In some embodiments, the lower end of the stack is formed of one or more axially displaced lower tubular shells which are concentrically spaced for forming annular inlets for admitting additional combustion air.
US2003/0059732 describes film cooling techniques and the maximum dilution of combustion products before they exit the system. This reference teaches use of segmented tubes placed above the combustion chamber to cool the products of the gas combustion. The system disclosed in this reference also includes one or more pairs of waste gas inlet ports and closure ports, wherein the inlet and closure port of each pair being located on opposing sides of the burn chamber.
The commonly used incinerator systems, such as disclosed in U.S. Pat. No. 6,146,131 and US2003/0059732 use flame-induced air flow, wherein the convection current generated by burners in the combustion chamber is used to draw more air towards combustor to achieve desired combustion.
Thus, there is a need for an improved apparatus, system and methods for smokeless burning of combustible gases and liquids with air to lessen the noise and to increase the efficiency whereby more fuel may be burned with less added motive forces such as steam, blower, etc.